schuchert - tdd.objectivec.XCodeProjectSetup

Why?

It took a bit of digging to come up with the steps required to get basic unit testing working in XCode. These steps borrow heavily from the following sites (in no order, because I don't remember what all it took to get this working):

Much of my confusion comes from the difference between using "raw" Objective-C (relatively easy) versus XCode and all that implies. In any case, that's the environment I'll be using for courses, so that's what I need to be able to get working.

What These Steps Describe

Technology:

XCode 3.2.1
The OCunit framework built-in to XCode 3.2.1
Cocoa Framework
Snow Leopard, though I suspect this will all work under any variant of 10.3 or later

These steps describe what you'll need to do to set up a framework, not an application. If you want to set up an application, review either of the bottom two links in the Why section.

Video Version

TDD & Objective-C in XCode: Getting Started from Brett L. Schuchert on Vimeo.

Setting up Project

In XCode create a new project: File:New Project or Command-Shift-N
Under the Mac OS X Templates, select Framework & Library
Select Cocoa Framework on the right-side, top pane and either click Choose or double-click
In the Save As box, enter a project name. I'll be using RpnCalculator
Select the directory under which to create your project. I'll be using /Users/schuchert/src/ObjectiveC/Practice
Click Save

At this point, you should have a window that resembles the following:

Configuring for Unit Tests

Under Groups & Files, select RpnCalculator and right-click (ctrl-click), select Add:New Target
Under Max OS X, select Cocoa
In the top-most right pane, select Unit Test Bundle and either double-click or click next
Under Target Name enter some descriptive name. I'll use UnitTests.
Click Finish
This should bring up the info window on the target:

Under the Direct Dependencies pane, click the + and add a dependency to RpnCalculator (double-click on RpnCalculator)
Close the info window

Adding a Test Fixture

Now you'll add a simple fixture with a failing test, then get the test to pass.

Create a new File, File::New or Command-N
Select Cocoa class under Mac OS X
In the upper-most right pane, select Objective-C test case class
Click Next (or double-click)
Under the File Name enter some sensible test name (making sure to leave the ".m" at the end of the name alone). I'll be using ANewlyCreatedRpnCalculatorShould
Under the Targets make sure to select UnitTests and to unselect RpnCalculator
Click Finish

Create a Failing Test

Update ANewlyCreatedRpnCalculator.h to resemble:

#import <SenTestingKit/SenTestingKit.h>
 
@interface ANewlyCreatedRpnCalculatorShould : SenTestCase {
}
 
@end

Update ANewlyCreatedRpnCalculator.m to resemble:

#import "ANewlyCreatedRpnCalculatorShould.h"
 
@implementation ANewlyCreatedRpnCalculatorShould
 
-(void)testWillFail {
    STAssertTrue(0, @"");
}
 
@end

Build to run the test

Let's assume the for building you'll want to run the tests every time.

Pull down the Project Menu, select Set Active Target and pick UnitTests
Bring up the Build window: command-shift-B or Build:Build Results
Click Build
The test should fail:

Get the test to pass

Update the assertion line in ANewlyCreatedCalculatorShould from:

    STAssertTrue(0, @"");

To:

    STAssertTrue(1, @"");

Save and re-build.
All tests should be passing:

Really Getting it all Tied Together

Now it's time to get the RpnCalculator framework linked into the test target.

Update the unit test (in ANewlyCreatedCalculatorShould.m):

#import "ANewlyCreatedRpnCalculatorShould.h"
#import "RpnCalculator.h"
 
@implementation ANewlyCreatedRpnCalculatorShould
 
-(void)testHave0InItsAccumulator {
    RpnCalculator *calculator = [[RpnCalculator alloc] init];
    STAssertEquals(0, calculator.accumulator, @"");
    [calculator release];
}
 
@end

This example imports a type that does not yet exist. So add it:

Create a new file: File:New or Command-N
Select Cocoa Class:Objective-C class
Click Next
Under File Name: enter: RpnCalculator making sure to leave the ".m" in place.
Under the Targets section, select RpnCalculator and de-select UnitTests
Click Finish
Edit RpnCalculator.h:

#import <Cocoa/Cocoa.h>
 
@interface RpnCalculator : NSObject {
    int accumulator;
}
 
@property (readonly) int accumulator;
 
@end

Edit RpnCalculator.m:

#import "RpnCalculator.h"
 
@implementation RpnCalculator
 
@synthesize accumulator;
 
@end

If you build now, you will get a linking error. Try it:

To Fix this:

In the main window, under Groups & Files, select RpnCalculator
In the top-most right pane, you'll see a list view; the first column has the name File Name.
Scroll down until you see RpnCalculator.framework
On the far-right side of that pane is a column with check boxes. Find the check box for the row containing RpnCalculator.framework and enable it:

Build again (Command-Shift B, click the build button)
You should have a successful build:

Congratulations

You have a project configured to run unit tests when built.

You can add "production" code to RpnCalculator and unit tests code to UnitTests.
By default, a build will build the RpnCalculator framework, then UnitTests and then execute the unit tests.

At this point, you can continue practicing Test Driven Development.